I have included in the function.php the following code:
function register_fields() {
include_once( get_stylesheet_directory() . '/inc/add-ons/font-awesome/acf-font-awesome-v5.php');
}
add_action('acf/include_fields', 'register_fields');
to include your plugin.
When I select an icon in my field, I found that was not load the icons, was appearing square in place.
So I checked the page code and saw the following line:
<link rel='stylesheet' id='acf-input-font-awesome-input-css' href='https://developer.adesign.com.br/orangeone/wordpress/wp-content/plugins/Applications/MAMP/htdocs/orangeone/wordpress/wp-content/themes/orangeone/inc/add-ons/font-awesome/css/input.css?ver=1.5' type='text/css' media='all' />
I hope it helps ??
Cesar